\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{circuitikz}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\ctikzset{bipoles/length=1cm}
\begin{document}
\small
\begin{circuitikz}[>=latex, scale=1.5,european]
  % \useasboundingbox(0.9,0)rectangle(5.1,5);
  \draw (-1.5,0)node[left]{$A$} to[R=$R_3$, *-*](0,1.0)node[above]{$B$};
  \draw (-1.5,0) to[R=$R_1$, *-*](0,-1.0)node[below]{$D$};
  \draw (0,-1.0) to[R=$R_2$, *-*](1.5,0);
  \draw (1.5,0)node[right]{$C$} to[R=$R_x$, *-*](0,1.0);
  \draw (0,1.0) to [rmeter, t=G] (0,-1.0);
  \draw (-1.5,0)--(-1.5,-2)to [battery2](1.5,-2)--(1.5,0);
  \draw[<-](-0.15,0.9)--++(-.3,-0.2)node[above]{$I_3$};
  \draw[->](0,1.0)--++(.3,-.2)node[above]{$I_4$};
  \draw[<-](-0.15,-0.9)--++(-0.3,0.2)node[below]{$I_1$};
  \draw[->](0,-1.0)--++(0.3,0.2)node[below right]{$I_2$};
  \draw[->](0,1.0)--(0,.5)node[right]{$I_g$};
\end{circuitikz}
\end{document}